SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'ef0d8c77897821e5ed6869584e8bc37950b4c016db8dad19e01b65cd515396b2' 
  AND token = 'Nl0psowJEl4fqsgh/V6Of6CYTA+p++ZErbf9WNFonvg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}